Flywheel Energy Storage Systems

Modern flywheel storages are based on proven principles and consist of a complex interplay of innovative components.
Basics of Flywheels

Our Gerotor HPS is based on a modern flywheel energy storage system. Flywheel energy storage systems have been developed and proven their worth for thousands of years. Modern components offer a multitude of new advantages for the use of this technology in different applications areas.

Innovative flywheel energy storages are reliable, clean and efficient energy storage systems.

Our Gerotor HPS is an electro-mechanical high-performance storages that stores energy kinetically in the form of a rotating mass and uses the inertia of the rotational mass to store or generate energy. Kinetic energy is the energy of movement and defined by the formula:

Kinetic energy = ½ (mass) x (velocity) ²

The present amount of energy and its duration is proportional to its mass and the velocity squared. Low-speed flywheels make use of the mass they are equipped with – more mass means more energy, and double mass equals double energy. High-speed flywheels make use of the speed they are turning with – the higher the speed, the higher the energy and double RPMs relates to quadruple energy.

Architecture of a flywheel storage system

In a flywheel storage system, kinetic energy is stored in the form of a rotation mass, with the flywheel being the heart of such a system. A flywheel system may include either mechanical or magnetic bearings housed in a vacuum-tight chamber. The evacuation reduces friction and increases the roundtrip efficiency.

The bearings support the rotor, maintaining its position and allowing it to rotate at high speeds. The type of bearings used can be determined by the speed of the flywheel, power and potential maintenance problems. Mechanical bearings are subjected to a constant load and require maintenance at certain intervals. Often, expensive magnetic bearings are used in high-speed flywheel systems in order to bypass maintenance times and further reduce friction losses. However, magnetic bearings are relatively expensive compared to mechanical bearings and not always necessary, since, for example, friction losses in industrial applications are not decisive and maintenance times of other components are required anyhow. In addition to the bearings, a typical flywheel system also consists of an electric motor generator and a rotor. The design of the rotor is important for determining the effectiveness as well as the efficiency of the system. The shaft of the flywheel is connected to an electric motor generator.

Using the stored energy in the rotating mass unloads the energy stored in the flywheel. When the device functions as a motor, energy is supplied to the flywheel, and when the device functions as a generator, energy is stored. The present amount of energy and its duration is determined by the mass and speed of the flywheel. Such produce high power output for short periods of time, a typical time period is 1-30 seconds.

Principles of a flywheel storage system


Most electrified machines and plants are capable of recuperation. Recuperation significantly improves the energy efficiency. Our Gerotor HPS offers the best solution in terms of roundtrip efficiency (RTE), high performance, low weight, temperature insensitivity, durability (10-20 years), low maintenance requirements and offers an excellent price / performance ratio.

Load Management

Many industrial processes are volatile and have very high power peaks. The Gerotor HPS shaves such power peaks or provides power at peaks when needed. This allows the connecting power and the provision charges to be significantly reduced. Downsizing of other components can further offset the initial investment costs.

Uninterrupted Power Supply (UPS)

The energy contained in the flywheel storage can bridge short-term power failures for a few seconds to a few minutes, until other power supply methods are available. Roughly 97% of all power failures are within 1-5 seconds. The characteristics of the short-term emergency power supply of a flywheel storage are mostly sufficient to transfer machines into a neutral working mode. Especially in areas of unstable power networks, cost-intensive production stoppages can be avoided.

General Advantages

High power density

Our flywheel storages provides much higher power density than batteries and higher energy densities than super-condensers.

Highest cycle stability and long durability

Flywheel storage systems have almost unlimited cycle stability and the longest life cycles of all available alternative storage systems.

Low maintenance requirements

The Gerotor HPS requires very little maintenance. Self-diagnosis results in avoidance of failures and therefore maintenance requirements are minimized.

Environmentally friendly

The environmentally friendly production process of components for our Gerotor HPS causes low CO2 emissions. Generally, flywheel storage systems do not contain toxic substances and are completely recyclable.

Fast amortization

An amortization (ROI) is usually given within 1-3 years. Often an immediate amortization can be achieved by downsizing other components and reducing the connecting power.

Temperature Insensitive

The Gerotor HPS can be operated at ambient temperatures of -25 ° C to 60 ° C

Improved power and grid quality

Power and grid quality can be improved by compensating for harmonic waves, flicker and reactive power. This applies to internal DC-link networks as well as cross-country power supply (harmonization of volatile and weak networks).

Intelligent data management

Measurement data of your machines and plants are the basis for an efficient industrial 4.0 and IIoT

Flywheel storages as an integral part of the IIoT? Learn more about the advantages of the Gerotor HPS in a digitalised world!